@stuff=($0.5,$0.5,$0.5) You're concatenating the value of the special variable $0 with 5. For the example you gave, this would fill @stuff with ('-e5', '-e5', '-e5'). Watch out for variable interpolation. perl -e "@stuff=('$0.5', '$0.5', '$0.5');my $x=0;foreach (@stuff){s/\$//; $x+=$_}; print $x" or perl -e "@stuff=qw($0.5 $0.5 $0.5);my $x=0;foreach (@stuff){s/\$//; $x+=$_}; print $x"